Mechanical fuzing system

ABSTRACT

An all mechanical fuzing system having an arming system, a stabilization timer, an antidisturbance device, a self-destruct timer, and a trip-line release mechanism. The above elements being interconnected so as to be able to (1) arm a mine, (2) actuate the traps associated with the mine, and (3) destruct the mine a predetermined interval of time after arming.

United States Patent [72] Inventor Norman F. Green Minneapolis, Minn.

Oct. 25, 1968 Sept. 7, 197 1 The United States of America as represented by the Secretary of the Air Force [21 Appl. No. [22] Filed [45] Patented [73] Assignee [54] MECHANICAL FUZING SYSTEM 6 Claims, 8 Drawing Figs.

[52] US. Cl 102/79, 102/4 [51] 1nt.Cl F42c 15/14 [50] Field of Search 102/7.2, 8,

References Cited UNITED STATES PATENTS 2,455,958 12/1948 Taylor 102/81 3,151,557 10/1964 Evanofi'etaL. 102/70 3,272,125 9/1966 Adams 102/70 3,330,209 7/1967 Kaiser 102/71 3,450,047 6/1969 Piskorski et a1 102/71 3,498,219 3/1970 Axelson 102/8 Primary ExaminerVerlin P. Pendegrass Att0rneys-Harry A. Herbert, Jr. and Jacob N. Erlich ABSTRACT: An all mechanical fuzing system having an arming system, a stabilization timer, an antidisturbance device, a self-destruct timer, and a trip-line release mechanism. The above elements being interconnected so as to be able to (1) arm a mine, (2) actuate the traps associated with the mine, and (3) destruct the mine a predetermined interval of time after arming.

PATENTED SEP 7 SHEET 2 OF 3 MECHANICAL FUZING SYSTEM BACKGROUND OF THE INVENTION This invention relates generally to fuzing systems, and more particularly, to an all mechanical fuzing system which can be used to (1) arm a mine, (2) actuate traps associated with a mine, and (3) destruct a mine after a predetermined time interval.

Mines are commonly associated with the defense of a territory, in that an area being evacuated is mined so that the enemy will be hindered and slowed down in occupying it. In this respect they differ from other ammunition and weapons that require the actual presence of troops to operate them, for mines are operated by the enemy against himself and are a hazard to him 24 hours a day. Land mines are placed on land or just beneath the surface to inflict damage on either personnel or equipment. They are primarily of the trap type, being initiated by unsuspected action of the enemy. If they are for the purpose of destroying vehicles, trucks, and tanks, they are called antitank mines, and if they are directed against personnel they are called antipersonnel mines. Beach defense mines are laid just under the water to defend beaches against landing craft. Since all mines, but particularly antipersonnel mines, can be hidden in a great variety of places and can be actuated in a variety of ways, some are called booby traps, because the boob or unsuspecting soldier may sit on something, pick something up, step on something, or trip over a wire, any one of which actions may actuate the mine or booby trap. They are laid near barbed wire, walls, evacuated houses-almost anywhere; their damage is usually to one or two soldiers, which hardly slows down thewar. But they make life miserable, break morale, slow down advances and occupation of captured territory, and distinctly discourage souvenir collectmg.

Antipersonnel mines are of the straight demolition type, similar to antitank mines, or of the fragmentation or bouncing Betty type wherein a projectile flies up in the air from the ground and detonates a few feet from the ground, spraying fragments in all directions. Booby traps not only can be constructed of antipersonnel mines but also can be improvised from demolition charges, shell, or any container to hold an explosive charge, and activated by any firing device.

The heart" of the mine lies in its fuzing system. For a mine to be fully effective the fuzing system must be able to perform a plurality of fuzing operations. For example, the fuzing system must be capable of l) arming the mine, (2) actuating the traps which are part of the mine, and (3) destructing the mine at a predetermined time after arming.

The fuzing systems heretofore in operation fell short in either one or all of the above operations. They failed to meet the performance standards necessary under battlefield conditions either because of malfunctioning of the fuzing system due to the highly complex nature of its construction or because of its undependable operation due to its simplified construction. It therefore became essential that a fuzing system be constructed that was of relatively simple construction yet of extreme dependability.

SUMMARY OF THE INVENTION The fuzing system of the instant invention is the type which is both of relatively simple construction and highly dependable; thereby overcoming the above-mentioned shortcomings of fuzing systems hereinbefore in use.

The instant fuzing system is entirely mechanical and therefore eliminates many of the difficulties encountered in the electrical or electromechanical fuzing systems of the past. Furthermore, the instant invention performs all of the necessary functions of a fuzing system; that is (l) arming the mine, (2) actuating the traps associated with the mine, and (3) destructing the mine after a predetermined interval of time.

' The fuzing system of the instant invention is capable of being mounted within any conventional mine. It is constructed of five basic parts; (I) an arming system, (2) a stabilization itiated by the spinup of the mine created when the mine is released from its dispenser. When the required spinup is reached, the fuzing system performs the following functions:

(I) it initiates the stabilization timer by disengaging it from stabilization timer release dogs, (2) it initiates the self-destruct timer by piercing a puncture diaphragm, and (3) it arms the fuze by carrying the detonator in line with a lead cup and a firmg pm.

After providing a short delay for mine impact and roll, the stabilization timer causes trip-line ejection. second delay interval is then provided for the mine to come to rest again. At the end of the second delay interval, the antidisturbance device is sensitized. The fuze is now fully armed andwill provide a detonation output when disturbed or at the end of the self-destruct delay period.

It is therefore an object of this invention to provide an all mechanical fuzing system.

It is another object of this invention to provide a fuzing system which arms a mine.

It is a further object of this invention to provide a fuzing system which actuates the traps associated with a mine.

It is still another object of this invention to provide a fuzing DESCRIPTION OF THE DRAWING FIG. 1 represents a plan view of a conventional mine which utilizes the all mechanical fuzing system of this invention;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 of this invention;

FIG. 3 is a cross-sectional view taken along line3-3 of FIG. 2 of this invention;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3 of this invention;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 4 superimposed on FIG. 3, wherein the phantom lines represent the armed position of this invention;

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 3 of this invention in a reduced scale;

FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 3 of this invention in a reduced scale; and g FIG. 8 is a view similar to FIG. 3 showing the fuzing system of this invention in its operative or armed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to FIGS. 1 and 2 wherein a mine [0 of conventional construction is shown. FIG. I sets forth the external configuration of the mine 10, making specific reference to the trip-line retaining springs I2 held in position by a trip-line release stem 14. FIG. I shows only one such set of trip-line retaining springs 12 and trip-line release stem 14; although any number may be used; for example, two of each being shown more clearly in FIG. 2. I

FIG. 2 shows the internal configuration of the mine 10, showing the location of the fuzing system 16 of this invention; The outer shell 18 of the mine 10 is of the fragmentation type containing a high explosive 20 therein. A plurality of trip-line target sensors 22 (only one of which is completely shown in the Figure) containing a trip-line 23, anchor 25 and spring 27,

are located within trip-line well 29. The interrelationship between the fuzing system 16 and the various elements of the mine will be explained in detail hereinbelow.

The all mechanical fuzing system 16 of this invention is shown in detail in FIGS. 3-8. The arming system 30 is shown in detail in FIG. 5. Referring now to FIGS. 4 and 5 of the drawing, it can be clearly seen that the centrifugal arming system 30 comprises of two pairs of centrifugal weights 32, only one pair of which is shown in detail in FIG. 5 since the other is a duplicate thereof. The detailed explanation will therefore make reference to only one of such pairs of weights as shown in FIG. 5. The weights 32 are spring loaded and held in position by spring 34 and remain together until spinup. Each weight 32 is interlocked with its mate by the arrangement shown in FIG. 5, using a gear and tooth arrangement 36. The weights 32 are so designed that their centers of gravity are the same distance apart as their pivot points and therefore the entire arming system 30 can be rendered insensitive to shock or impact.

When the mine and thereby the fuzing system 16 is spun up to arming speed about its axis of rotation 38 (shown in FIGS. 4 and 5) by releasing it from a dispenser, the centrifugal force on each weight 32 overcomes the respective force exerted by spring 34 and causes the weights to rotate outward approximately 30 (shown in phantom in FIG. 5). One weight 32 of each pair has a slider release tab 40 located thereon. As the weights swing outwardly, the tab 40 rotates and releases slider 42.

The slider 42 is held in position by a tab 44 integral therewith which bears against the slider release tab 40 (shown in FIG. 5). A spring 46 forces the slider 42 to move in the upward direction (shown in FIG. 8) when the slider release tab 40 releases tab 44. The slider 42 further has therein a detonator 48 (shown in FIG. 3) and an upstanding tab 50 (shown in FIG. 5).

Referring now to FIG. 3, it can be seen that the stabilization timer 52 is made up of a dashpot device 53 utilizing any suitable high-viscosity fluid material such as silicone rubber gum working fluid 54. The silastic gum 54 is confined in a cylindrical chamber 56 and held therein by any suitable sealant such as plastic film seal 58. A metering disc 60, also in the chamber 56, is held against the plastic seal 58 by a weak compression spring 62. A heavily spring-loaded plunger assembly 64, comprising a plunger 66 and a biasing means such as spring 68 confined within cylindrical housing 70, is located just outside the plastic film seal 58. Reference is now made to FIG. 5 wherein it is shown that the spring-loaded plunger assembly 64 is held in a cocked position by a dog 72 which engages the upstanding tab 50 on slider 42. Movement of the slider 42 in the upward direction upon arming, as hereinbefore described, releases the dog 72 and initiates the timer 52. As shown in FIG. 8, upon timer initiation, the tip of the plunger 66 penetrates the plastic film seal 58 and contacts the metering disc 60, slowly driving it toward the far end of the chamber 56. The rate of movement of the metering disc 60 is greatly retarded by the highly silastic gum 54 which must be displaced around the disc 60 as it moves. As the plunger assembly 64 moves, it performs two functions. First, it activates the tripline release mechanism 65 (shown in FIG. 5) by means of a stepped cam arrangement 74 (shown in FIG. 3) and second, it sensitizes the antidisturbance device 76 (shown in FIG. 3), the operation of which will be explained hereinbelow.

Referring now to FIGS. 3, 4 and 7, the mechanical antidisturbance device 76 is shown to be made up of a stationary magnet 78 rigidly mounted to the fuze housing 79, a rotating magnet 80 secured by any suitable securing means such as by being pressed-fitted to a firing pin shaft 82, and an eccentric, free-swinging antidisturbance weight 84. There are bearing fits 85 between the shaft 82 and the stationary magnet 78, the shaft 82 and the weight 84, and the shaft 82 and the fuze housing 79. A tab 86 from the stabilization timer 52 locks the rotating magnet 80 so that its poles are aligned north to north and south to south with the stationary magnet 78 in a magnetrepulsion position. While locked, the magnets are also held apart by a key 88 on the firing pin shaft 82 which bears against the stationary magnet 78, holding the magnets apart under impact conditions.

After allowing time for mine impact, roll, and trip-line ejection and for the antidisturbance weight 84 to seek its stabilization point orientation, the locking tab 86 of the stabilization timer 52 disengages from the rotating magnet and moves to a point between the magnet 80 and the antidisturbance weight 84 shown in FIG. 8, thereby sensitizing the mine 10. Since the two magnets 78 and 80 are in a state of mutual repulsion, the rotating magnet 80 is forced against the weight 84 and is thus frictionally coupled to it so that any movement of the weight 84 will result in an angular displacement of the rotating magnet 80.

Thus any disturbance of the mine moves weight 84 thereby moving magnet 80 from its magnet-equilibrium position. Once displaced from its magnet-equilibrium position, the rotating magnet 80 will turn 180 (to the position shown in FIG. 8), due to its magnetic interaction with magnet 78, and becomes attracted to the stationary magnet 78. Since the key 88 on the firing pin shaft 82 has in turn, rotated to line up with the key way slot 90 cut in the stationary magnet 78, this magnetic attraction will result in movement of the rotating magnet 80 toward the stationary magnet 78, thus driving the firing pin 92 located on firing pin shaft 82 into the detonator 48 (shown in FIG. 8).

The self-destruct timer 94 is of a pressure-decay type and incorporates a spring-loaded piston 96 having a spring and a bellows seal 98. The chamber or self-destruct timer housing 100, which encloses of the outside bellows 98 plus the head space 97 of the piston 96, is pressurized with any suitable gas such as CO through a fill tube (not shown) to approximately 400 p.s.i. during assembly. During the first few hours after pressurization, a small portion of the filled gas permeates through the silicone rubber restrictor 102 and a pair of porous metal backup plates 103 and pressurizes the vent holes 105 between the restrictor 102 and puncture diaphragm 104 made of any suitable material, thus establishing pressure equilibrium across the restrictor 102. Upon pressurization, the piston 96 is driven outwardly to its position in FIG. 3 so that the end 107 of the piston rod 96 extends beyond the timer housing 100. The timer 94 remains in this condition until initiation.

As shown in FIG. 8, the time delay function is initiated when a puncture pin 106 located on the leading face of slider 42 penetrates the puncture diaphragm 104. When this occurs, the gas is permitted to bleed from the chamber 100 at a controlled rate through the silicone rubber restrictor 102, thus causing the pressure within chamber 100 to decay with time. When the internal pressure has decayed to 100 p.s.i. the piston 96 begins to move. When the pressure level reaches 50 p.s.i., the end 107 of the piston rod 96 has withdrawn far enough to release the self-destruct leaf spring 109 (see FIGS. 8 and 6). This leaf spring 109 then engages a spline profile 111 on the end of the antidisturbance weight 84 and causes the weight to rotate (shown clearly in phantom in FIG. 6).

As best shown in FIGS. 5 and 8, the trip-line release mechanism 108 is initiated by the stepped cam portion 74 of the plunger assembly 64 which allows the trip-line release pin to index outwardly (shown in phantom in FIG. 5), thereby permitting the trip-line release levers 112 which are pivoted about shaft 113 to rotate under action of their respective torsion springs 117. The resulting rotational movement is transferred to the outer surface of the mine 10 by the trip-line release shaft 113. This movement is used to rotate trip-line release stem 14, thereby disengaging the trip-line retaining springs 12 from the trip-line target sensors 22. The trip-lines 23 and their respective anchors 25 are then released from the trip-line well 29 and projected by spring 27 to a nearby location.

MODE OF OPERATION The all mechanical fuzing system 16 of this invention is initiated by a spinup of the mine produced after the mine 10 is released from its dispenser (not shown). Referring now to FIG. 5, when the required spin rate is reached, the arming weights 32 rotate outward (as shown in phantom in FIG. 5) and release the slider 42. As the slider 42 snaps to the armed position (shown in FIG. 8) under the force of spring 46, it performs three functions: (1) it initiates the stabilization timer 52 by disengaging the plunger assembly 64 from the upstanding tab 50 located on slider 42; (2) it initiates the self-destruct timer 94 by piercing the puncture diaphragm 104; and (3) it arms the fuze by carrying the detonator 48 in line with the lead cup 115 and the firing pin 92.

After providing a short delay from mine impact and roll, the stabilization timer 52 causes trip-line ejection by allowing the trip-line release pin 110 to index outwardly. A second delay interval is then provided for the mine to come to rest again. At the end of the second delay interval, the antidisturbance device 76 is sensitized by disengagement of the locking tab 86 of the plunger assembly 64 from the rotating magnet 80. The fuzing system is now fully armed and will provide a detonation output under the following conditions:

1. When the mine 10 is disturbed or moved by a person or object. Such movement also moves the antidisturbance weight 84 which causes simultaneous angular displacement of the rotary magnet 80 which is frictionally coupled thereto (shown in FIG. 3). Once displaced from its magnet-equilibrium position the rotating magnet 80 will turn 180 (to the position shown in FIG. 8), due to its magnetic interaction with stationary magnet 78, and becomes attracted to the magnet 78. Since key 88 on the firing pin shaft 82 now lines up with the key way slot 90 in the stationary magnet 78, the magnetic attraction will result in movement of the rotating magnet 80 toward the stationary magnet 78, thus driving the firing pin 92 located on firing pin shaft 82 into the detonator 48, thereby detonating the mine 10.

2. When sufficient gas has been permitted to bleed from the self-destruct timer chamber 100 at a controlled rate through the silicone rubber restrictor 102. With time the pressure level within the chamber 100 becomes sufficiently low so that the piston rod 96 withdraws far enough under the action of spring 95 to release the self-destruct leaf spring 109 (see FIGS. 3 and 6). This leaf spring 109 then engages a spline profile 111 on the end of the antidisturbance weight 84 and causes the weight to rotate (shown clearly in phantom in FIG. 6), thereby initiating the detonating operation set forth hereinabove.

3. When the trip-lines 23 located on mine 10 are disturbed by a person or object. The operation of the trip-line release mechanism 108 is initiated by the stepped cam portion 74 of the plunger assembly 64 which allows the trip-line release pin 110 to index outwardly (shown in FIGS. 3 and 5), thereby permitting the trip-line release levers 112 to rotate under the action of torsion springs l 17. The resulting rotational movement is transferred to the outer surface of the mine 10 by the tripline release shaft 113. This movement rotates the trip-line release stem 14, thereby disengaging the trip-line retaining springs 12 from the trip-line target sensors 22. The trip-lines 23 and their respective anchors 25 are then released from the trip-line well 29 and projected by springs 27 to a nearby location. Disturbance of the trip-line, moves the mine itself, thereby moving the antidisturbance weight 84 initiating the detonating operation set forth above.

Although the invention has been described with reference prisin at least one pair of weights, said pair of weights pivota ly held in position about a central axis by a biasing means, one weight of said pair of weights having a tab thereon for holding said slider in the inoperative position, a stabilization timer means operably associated with said slider, said stabilization timer means comprising a dashpot device and a plunger assembly, said plunger assembly held in the inoperative position by said slider when said slider is in the inoperative position, an antidisturbance means, said antidisturbance means having a firing pin shaft, a self-destruct timer means operably associated with said antidisturbance means and said slider whereby spinning of said fuzing system about said central axis causes separation of said weights thereby moving said tab out of the slider holding position enabling said slider to move to the operative position wherein said firing pin shaft is positioned operably opposite said detonator and whereby movement of said slider to the operative position releases said plunger assembly and enables said plunger assembly to move into the operative position wherein said plunger assembly penetrates said dashpot device thereby sensitizing said fuzing system.

2. An all mechanical fuzing system as defined in claim 1 wherein said antidisturbance means further comprises a stationary magnet fixedly secured to said housing, a rotating magnet fixedly secured to said firing pin shaft, an eccentric antidisturbance weight loosely secured to said firing pin shaft, said rotating magnet being aligned north to north and south to south with said stationary magnet in a magnet repulsion position, said rotating magnet being held in said magnet repulsion position by a tab fixedly mounted on said plunger assembly, whereby movement of said plunger assembly into the operative position moves said tab into position between said rotating magnet and antidisturbance weight thereby releasing said rotating magnet and sensitizing said antidisturbance means.

3. An all mechanical fuzing system as defined in claim 2 wherein said self-destruct timer means comprises a gas filled chamber, a spring-loaded piston rod within said chamber, a self-destruct leaf spring adjacent one end of said chamber and in operative alignment with said antidisturbance weight, and a puncture diaphragm sealing the other end of said chamber, one end of said piston rod holding said leaf spring in an inoperative position, whereby movement of said slider to said operative position causes a pin mounted on said slider to puncture said puncture diaphragm thereby slowly releasing the gas within said chamber and sensitizing said self-destruct timer means.

4. An all mechanical fuzing system as defined in claim 3 wherein said plunger assembly comprises a spring biased plunger and said dashpot device contains a high-viscosity fluid material therein, said fluid material retarding the penetration of said plunger into said dashpot device when said plunger assembly is in the operative position.

5. An all mechanical fuzing system as defined in claim 4 wherein said slider is spring biased into the operative position.

6. An all mechanical fuzing system as defined in claim 1 wherein said housing further contains a trip-line release means operably associated with said stabilization timer means. 

1. An all mechanical fuzing system comprising a housing, said housing containing therein a slider having a detonator thereon, a centrifugal arming means, said arming means comprising at least one pair of weights, said pair of weights pivotally held in position about a central axis by a biasing means, one weight of said pair of weights having a tab thereon for holding said slider in the inoperative position, a stabilization timer means operably associated with said slider, said stabilization timer means comprising a dashpot device and a plunger assembly, said plunger assembly held in the inoperative position by said slider when said slider is in the inoperative position, an antidisturbance means, said antidisturbance means having a firing pin shaft, a self-destruct timer means operably associated with said antidisturbance means and said slider whereby spinning of said fuzing system about said central axis causes separation of said weights thereby moving said tab out of the slider holding position enabling said slider to move to the operative position wherein said firing pin shaft is positioned operably opposite said detonator and whereby movement of said slider to the operative position releases said plunger assembly and enables said plunger assembly to move into the operative position wherein said plunger assembly penetrates said dashpot device thereby sensitizing said fuzing system.
 2. An all mechanical fuzing system as defined in claim 1 wherein said antidisturbance means further comprises a stationary magnet fixedly secured to said housing, a rotating magnet fixedly secured to said firing pin shaft, an eccentric antidisturbance weight loosely secured to said firing pin shaft, said rotating magnet being aligned north to north and south to south with said stationary magnet in a magnet repulsion position, said rotating magnet being held in said magnet repulsion position by a tab fixedly mounted on said plunger assembly, whereby movement of said plunger assembly into the operative position moves said tab into position between said rotating magnet and antidisturbance weight thereby releasing said rotating magnet and sensitizing said antidisturbance means.
 3. An all mechanical fuzing system as defined in claim 2 wherein said self-destruct timer means comprises a gas filled chamber, a spring-loaded piston rod within said chamber, a self-destruct leaf spring adjacent one end of said chamber and in operative alignment with said antidisturbance weight, and a puncture diaphragm sealing the other end of said chamber, one end of said piston rod holding said leaf spring in an inoperatIve position, whereby movement of said slider to said operative position causes a pin mounted on said slider to puncture said puncture diaphragm thereby slowly releasing the gas within said chamber and sensitizing said self-destruct timer means.
 4. An all mechanical fuzing system as defined in claim 3 wherein said plunger assembly comprises a spring biased plunger and said dashpot device contains a high-viscosity fluid material therein, said fluid material retarding the penetration of said plunger into said dashpot device when said plunger assembly is in the operative position.
 5. An all mechanical fuzing system as defined in claim 4 wherein said slider is spring biased into the operative position.
 6. An all mechanical fuzing system as defined in claim 1 wherein said housing further contains a trip-line release means operably associated with said stabilization timer means. 